Hydrolysis

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Technology
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Technology details
Name: Hydrolysis
Category: Primary processing
Feedstock: lignocellulosic biomass
Product: Sugars and organic acids

Hydrolysis (/haɪˈdrɒlɪsɪs/; from Ancient Greek hydro- 'water', and lysis 'to unbind') is a chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.[1] In lignocellulosic biomass, the cellulose and hemicellulose breaks down into individual sugars. Hemicellulose is easier to hydrolyse than cellulose.[2] The result of hydrolysing hemicellulose and cellulose are sugars (glucose, mannose, galactose, (C6) and xylose, arabinose (C5)) and organic acids (formic acid and acetic acid).[3]

Feedstock

Origin and composition

Hydrolysis can be performed as a pretreatment on any biowaste with a high lignocellulose content. Lignocellulose is typically the nonedible part of a plant, composed of a complex of cellulose, hemi-cellulose and lignin. In order to make the cellulose available for further processing, in the form of its monomeric sugars, they can be hydrolysed. Suitable feedstocks include grasses, straw, leaves, stems, shells, manure, paper waste, and others. The ratio between cellulose, hemi-cellulose and lignin varies wildly depending on the specific feedstock.[4]

Pre-treatment

Process and technologies

Acid

Acid hydrolysis is a hydrolysis process in which a protic acid is used to catalyze the hydrolysis reaction. A strong acid, such as formic, hydrochloric, nitric, phosphoric, or sulphuric acid can be used in concentrated or diluted form. Concentrated acid (10-30 %) can penetrate the lignin structure and break down the cellulose and hemicellulose to individual sugars at low temperature and with high yield. Downsides are the high acid consumption and high corrosion potential. These downsides are circumvented with the use of diluted acid (2-5 %). However, in the latter case, higher temperature is required, which can lead to side product formation such as furfural and 5-hydroxymethyl-furfural.[4]

Alkali

Alkaline hydrolysis refers to hydrolysis reactions using hydroxide, commonly from sodium hydroxide or calcium hydroxide. The hydroxide breaks down the lignin bonds to make the cellulose more accessible. The reaction proceeds at lower temperature and pressure and residual alkali can be recycled. However, the pretreatment does result in irrecoverable salts in the product.[5]

Salt

Hydrolysis can be further improved by the addition of salts, such as metal salts or sulphite salts.

Metals salts

Acid hydrolysis can be stimulated by the addition of metal chlorides. Metals such as aluminium, calcium, copper, iron, and zinc can be used to increase the sugar yield.[6]

Sulphite salt

No details on sulphite salt hydrolysis given yet.

Solvent

Solvents can be added to improve the hydrolysis process. This is similar to arganosolv pulping, but without the delignification as goal.[7]

Organosolv

In an organosolv hydrolysis organic solvents are added to the process, usually performed at high temperatures (100-250 °C). This can be combined with a catalyst such as HCl or H2SO4.[7] For example, in acid-acetone pre-treatment biowaste is treated with an acid such as phophoric acid and then mixed with pre-cooled acetone.[6]

Ionic Liquids

Ionic liquids are solvents that can be used for biomass pretreatment, fractionation, and dissolution. During IL pretreatment, a cellulose-rich fraction can be generated through the degradation and removal of a large portion of lignin and hemicellulose [8]

Product

No product description given yet.

Post-treatment

Technology providers

Technology comparison
Company name Country Technology category Technology name TRL Capacity [kg/h] Catalyst loading [wt %] pH Pressure [bar] Reactor Residence time [h] Temperature [°C] Feedstock: Food waste Feedstock: Garden & park waste
Company 1 [Country HQ location] [Technology category (if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] [Technology name (the "branded name" or the usual naming from company side)] [4-9] [numeric value]
Company 2 [Country HQ location] [(if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] [Technology name (the "branded name" or the usual naming from company side)] [4-9] [numeric value]

NextChem

Valmet Oyj

Hydrolysis provider
General information
Company: Valmet Oyj 21-04-27 Tech4Biowaste rect-p.png
Country: Finland
Contact:
Webpage: https://www.valmet.com/
Technology and process details
Technology name: BioTrac Technology category: Pre-processing (Chemical processes and technologies)
TRL: 9 Capacity: biomass feed up to 800 tonne/day kg·h-1
Agitator: Atmosphere:
Catalyst: Acidic conditions Controlled parameters:
Temperature: High °C Catalyst: Acidic conditions
Processable volume: L Reactor: Horizontal tube reactor
Reactor material: Safety restrictions:
Temperature: High °C Other:
Feedstock and product details
Feedstock: All lignocellulosic biomass, including wood and forestry residues, wheat straw, corn stover and bagasse Product:

Open access pilot and demo facility providers

Pilots4U Database

Patents

Currently no patents have been identified.

References

  1. Wikipedia, 2002: Hydrolysis 2002, Last access 2021. https://en.wikipedia.org/wiki/Hydrolysis
  2. P. Lenihan, A. Orozco, E. O’Neill, M.N.M. Ahmad, D.W. Rooney, G.M. Walker, 2010-01-15: Dilute acid hydrolysis of lignocellulosic biomass. Chemical Engineering Journal, Vol. 156, (2), 395–403. doi: https://doi.org/10.1016/j.cej.2009.10.061
  3. Katarzyna Świątek, Stephanie Gaag, Andreas Klier, Andrea Kruse, Jörg Sauer, David Steinbach, 2020-04-17: Acid Hydrolysis of Lignocellulosic Biomass: Sugars and Furfurals Formation. Catalysts, Vol. 10, (4), 437. doi: https://doi.org/10.3390/catal10040437
  4. a b Alessandra Verardi, Isabella De Bari, Emanuele Ricca and Vincenza Calabrò, 2012: Hydrolysis of Lignocellulosic Biomass: Current Status of Processes and Technologies and Future Perspectives. Bioethanol. Marco Aurelio Pinheiro Lima and Alexandra Pardo Policastro Natalense (Ed.). IntechOpen, {{{place}}}.
  5. S. Niju, M. Swathika, M. Balajii, 2020-01-01: Pretreatment of lignocellulosic sugarcane leaves and tops for bioethanol production. Lignocellulosic Biomass to Liquid Biofuels, Vol. , 301–324. doi: https://doi.org/10.1016/B978-0-12-815936-1.00010-1
  6. a b Amit K. Jaiswal, Rajeev Ravindran, 2016-01-01: A comprehensive review on pre-treatment strategy for lignocellulosic food industry waste: Challenges and opportunities. Bioresource Technology, Vol. 199, 92–102. doi: https://doi.org/10.1016/j.biortech.2015.07.106
  7. a b Valery B. Agbor, Nazim Cicek, Richard Sparling, Alex Berlin, David B. Levin, 2011-11: Biomass pretreatment: Fundamentals toward application. Biotechnology Advances, Vol. 29, (6), 675–685. doi: https://doi.org/10.1016/j.biotechadv.2011.05.005
  8. Moyer, P., Kim, K., Abdoulmoumine, N. et al., 2018: Structural changes in lignocellulosic biomass during activation with ionic liquids comprising 3-methylimidazolium cations and carboxylate anions 27/09/2018, Last access 06/12/2021. https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-018-1263-0